More and more, people are communicating with others in the online social networking services. For example, the social networking service, Twitter, reports that its users post or repost at least 400 million “tweets” each day. Similarly, the social networking service, Facebook, reports that there are 936 million active users each day, each interacting with others via posts and messages. Indeed, the volume of social communications that occur within all of the social networking services is staggering.
Naturally, the subject of the social communications is dynamic, often, but not exclusively, driven by current events. As a consequence, a topic that might be treated by a large number of the people in the social sphere (those communicating online via one or more social networking services) typically enjoys only fleeting popularity.